Automatic telephone system



J. WICKS AUTOMATIC TELEPHONE SYSTEM March 18, 1930.

4 Sheets-Sheet 1 Original Filed May 6, 1920 HHL L I'WWTT Jul-m .Mwks

March 18, 1930. J, w c s 1,751,260

AUTOMATIC TELEPHONE SYSTEM Original Fil'e'd May 19 4 Sheets-Sheet 2 hwas (wo 8% J. WICKS AUTOMATIC TELEPHONE SYSTEM March 18, 1930.

Original Filed May 6. 1920 4 Sheets-Sheet 3 GS V v Inusn or Jul-m Drlmksflm H J. WICKS AUTOMATIC TELEPHONE SYSTEM Original Filed May 3. 1920March 18, 1930.

4 Sheets-Sheet 4 WQ %3 wwwm @ww Patented Mar. 18, 1930 arr N oFFic JOHNWICKS, 01-? OAK PARK, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC, INC., OFCHICAGO, ILLINOIS, CORPORATIGN 0F DELAVARE AUTOMATIC TELEPHONE SYSTEM.

Original application filed. May 6, 1920, Serial No. 379,217. Dividedand. this application filed December My invention relates in general toautomatic telephone systems, but is concerned more particularly with'theprovision of an improved connector circuit for use in applying asemiselective ringing scheme to an auto matic system.

There are various other features disclosed, but not claimed, these otherfeatures being covered by icks Patent No. 1,586,057, issued May 25,1926, and a second Wicks Patent No. 1,681,351, issued June 7, 1927. Thepresent application is a division of the said first mentioned patent.

Referring to the drawings, comprising Figs. 1, 2, 3, and i, I have showntherein by means of the usual circuit diagrams the apparatus required toestablish a complete connection from a toll line terminating in jack J,

Fig. 1, to a local subscribers station A, Fig. 4.

This apparatus comprises the cord circuit 0, Fig. 1, located at a tolloperators position in a toll switching station or office; the twoconductor trunk line extending from jack J in the toll switching officeto the toll first selector D, Fig. 2, in a main exchange of the system;the toll transmission repeater E; the toll second selector F, Fig. 3;and the combination toll and regulator connector H, Fig. 4. Therepeater, second selector, and connector mentioned are in the sameoliice or exchange as the toll iirst selector D, which as indicatedabove may be one of the main offices or exchanges of a largemulti-oifice system. In addition to the abovel have also shown meanscommon to all'the trunk lines ext-ending from the toll switching ofiiceto the local. ofice, and which is used to collect or refund depositedcoins at any subscribers station, such as station A with which it may beconnected via the toll service trunking system. This additional means orapparatus comprises the special cord circuit 0, Fig. 1, which specialcord-circuits may be supplied in quantities of one or two per position;the trunk line extending from jack J in the toll switching office to thelocal office; and the special connector M, Fig. 2, in which the saidtrunk line terminates and which has access to all the toll firstselectors such as the selector D. 4

Serial No. 74,6?9. i

In view of the well known character of the apparatus and thedescriptions thereof in the publications previously referred to, I

will not describe such apparatus in detail in the present application,but will proceed at 5 once to explain the operation of the circuits witha view to pointing out the new improvements. For this purpose it will beassumed that the subscriber at substation A, F ig. 4, has placed a longdistance call with a toll recording operator and that the ticketcontaining the usual data concerning the desired connection has beenforwarded to the toll operator having the cord circuit 0, Fig. 1,

cord circuitO in the said jack J, the double throw listening and callingdevice K being thrown to callingposition at'thesame time. Upontheinsertion of the plug in the jack J a circuit is completed forrelays20 and 21 in i series; and the latter relay, upon energiz ing,lights the busy lamp L at its armature 23,-establishes a locking circuitfor itself at its armature 2ft, and at its armature 25 prepares acircuit whereby relay 22 may later be bridged across the trunkconductors 30 and 31, this circuit being open for the time being,however, at armature 26 of relay 20, which relay pulls up in series withrelay 21.

It is understood that the outgoing trunk jacks. and lamps are multipledat other opera ators positions in the'usual manner, and the multiplebusy lamps at the other positions are, of course, lighted in parallelwith lamp L The key K being in calling position, as be-' fore stated,the operators head set, including the calling device S in seriestherewith, will tor D over the trunk conductors and 31 in series. Uponthe completion of this circuit the line relay 51 is energized and closesthe circuit of the slow acting release'relay '52. Upon energizing, thelatter relay prepares the'selector switch foroperation in its verticalmovement in the usual manner.

The toll operator will now operate her calling device S in accordancewith the telephone number of the subscriber at substation A.

When the calling device dial is operated in accordance with the firstdigit of the number, a series of interruptions is produced in thecircuit of the line relay 51 of the toll selector D. The line. relay '51is,-therefore, deenergized a plurality of times corresponding to thedigit called, and at each deenergization sends a current impulse throughthe slow acting series relay 53 and the vertical magnet 56 to battery.By the operation of the'vertical magnet the switch shaft is raised stepby step until the wipers '707 3, inclusive, stand oppo-- site thehorizontal level of bank contacts which are terminals of trunklinesleading to the desired thousand group. The slow actrelay 53 isenergized in series with the vertical magnet, maintaining its armaturecontinuously attracted during the vertical operationof the switch, andat the first upward movement of the switch shaft closes a circuit forthe stepping relay 54. Upon energizing, relay 54 establishes a lockingcircuit for itself at its upper armature and at its lower armatureprepares a circuit for the rotary magnet 57 7 At the end of thevverticalmovement of the switch, the slow acting relay 53 is deenergized andcompletes the aforesaid circuit for the rotary magnet, whichisaccordingly energized and advances the wipers 70-7 3, in-

- clusive, into engagement with the first set of bank contacts in thelevel opposite which they were raised. 1 Near the end of its stroke therotary magnet breaks thelocking circuit of the stepping .relay 54, whichis accordingly deenergized to open the circuit of the rotary magnet Boththe rotary magnet 57 and the stepping relay 54'hav'ing deenergized, theoperation now depends upon whether; the test contactwith which the testwiper 71 is in engagement is busy or is not busy If thistest contact isbusy, it will have a round poten- V tial upon it and'a circuit 'will beestablished byway of the said test wiper, whereby'the stepping relay 54is again energized to again close the circuit of the rotary magnet .57,

which in turnoperates to advance the switch wipersinto engagement withthe next setof bankcontacts; This operation continues as long asthe testwiper 71 continues to engage grounded test contacts. As soon. as thefirst nonegrounded test contact is reached, which.

we will assinne to be the testcontact75 associated with the trunk lineextending to the repeater E, the stepping relay 54 will not again beenergized, and the rotary movement of the switch will cease. Theswitching relay 50, which heretofore has been short cirthat the steppingrelay 54 is not energized.

Upon energizing, relay 50 connects the grounded conductor 58to the testwiper 1 at armature 61; opens the circuit of the release 1 magnet "atits armature 62; and at its armatures and 64 disconnects the incomingtrunk line conductors 30 and 31 I"romfthe windings of the linerelay 61andextends them by way of wipers and 73, bank contacts "4'4 and 77, lefthand windings of the repeating coil R, and normally closed con: tactsor" the relay 101 to the upper and lower windings, respectively, ofthe'line relay 104 of the toll transmission repeater E. The line relay104 is accordingly energized and closes a circuit for theslow actingrelease relay 105 which, vupon energizing in turn, closes the talkingconductors through the repeater by means of its armatures and 118, andalso at its armature 116 completes a holding circuit in the usual mannerwhich extends? by way of conductor 144 back to the selector D where itserves to maintain the switching relay 50 energized throughout theconnection."

Ground'potential is also'placed on the multiples of' test contact 75 bymeans of thiscirselected trunk busy cuit inorder to make the to otherselectors. p V I When the line relay 104 ofthe repeater E was energizedas previously explained, a control or operating circuit extending to theline relay 1510f the toll second selecter F, Fig. 3.

completed as follows: Ground a r G armature 126 and t-s work ng contact,conductor 143, armature and its res contact, andthe winding 01 thelinerelay 151 to battery. 7 Upon theclosure oi the above circuit, theline relay 151 is energized andconie .pletes aw circuit-for the slowacting release relay 152 inthe usual manner.

gizing, relay 152 grounds the release trunk Upon 'enerconductor144locallyat'its'upper armature,

and at its lower armature prepares the .Cli'

cuits oi' the selector for the vertical oper- 9 ion thereof LU A I r Thetoll operator may new 0 aerate the dial of her calling deviceS. in"accordance with thesecond digit in thenumber of thesub scriher atsubstation A. The interruptions produced bythis operation are repeatedby V the line reiay 104 ofthe repeaterE, which relay causes a ser es ofthe linerelay 151 of the line relay 151 itlalso sends a series ofdeenergizations. of selects-r5, While the line relay104 is repeatingiinpuises to in inclusive, in engagement with bank co pulses through theslow acting relay 106, which operates to disconnect the A. C. relay 121and also to short circuit the lower right hand winding of the repeatingcoil These operations render the control circu' more eliicient. The tollsecond selector F is very similar to the selector D and its operation,therefore, will not be described in detail. will be sufficient to saythat the deenergizations of the line relay 151 bring about the operationof the vertical magnet through the mediun'i of which tie s raised stepby step until the wipers 70 inclusive, stand opposite the how 1i or"bank contacts which are terminals 0; t lines leading to the desiredgroup of: ncctor switches. The slow acting relay is energized in serieswith the vertical magnet and at the first upward step or the rattclosesthe initial energizing circuit of the stepping relay by way of the oilnorm contact springs 150. The stepp locks itself as usual and prepares a01 for the rotary magnet 15?. At the end of .e vertical movement of theswitch, the slew acting relay 153 is crgized and, the switch wipers arerotated in rch of an idle trunk line by means of to net 157, which iscontrolled by the sre lay 15a and the'test wiper 171. l Vhcn the lietrunk line is reached, which we will assume to be the trunk line(3011)1i ductors 178-181, inclusive, the rota ion o switch will cease,leaving the wipers 1701'"" 17 l-177, inclusive. The switchir is nowenergized and at its armati 163 connects the tall ngconduct, i 1 145with the line wipers 170 and 173, re-

spectively. Relay 150 also extents conductors 1&2 and 143 by of itsarmature 162 and 160, wipers 171 and 172, and Jank contacts 175 and 1. 6to conductors 170 and 180. The conductor 143 is included in the controlcircuit of the toll selector 1 and when it is extended as abovementirned. line relay 151 and the release rela the selector are, ofcourse, deen selector being maintained in op' tion by the continuedenergizatio switching relay 150, which is ground over the conductor 14 ithe repeater E.

The switch control circuit having been tended, as above stated, to theconductor 180. it may be further traced by way of the said conductor180, the upper winding of the re- 4:, contact springs controlled bybridge relay 200, and the upper winding of the connector for verticaloperation in the 305, and 306 which terminates in bank contacts 301,302, and 303,respectively, Fig.

These bank contacts are assumed to be located the banks of one or theregular selectors referred to, and the ground pot ntial upon conductor305, and the test contact 302 and its multiples, render the connector Hbusy.-

A branch of the conductor 305 may be traced from junction point 306 byway of conductor 305, winding of relay 207, conductor 179, bank contact17 5, Wiper 171, armature 162 and its working contact, conductor 142,armature 128 and its resting contact, and the resistance '111 tobattery. By

current flow over the above circuit the relay 207 is energized and atits armatures 236 and 237 prepares circuits for the ring cutoff relay205 which will be explained later. Relay 207 also closes a circuit forthe switching relay 20% by means or" its armature 238, and the latterrelay, upon energizing, produces a number of circuit changes in theconnector which are brought about for the purpose or enabling it tofunction as a toll connector rather than as a regular connector. Thesecircuit changes include the opening of the permanent locking circuit ofthe ring cutofi relay 205 at armature 225, the shifting of the lockingcircuit oi the busy test relay 206 at armature 224, the disconnection ofthe regular trunk line conductors and 306 at armatures 223 and 226, andthe preparation of a supervisory signaling circuit for the toll operatorat armature 223. These circuit changes and the results effected, therebywill be mentioned more in detail hereinafter. Before proceeding turtherwith the explanation a few more details concerning relays 207 and 204may be inserted wlth benefit. Relay 207 is'ot relativelylow resistance,and the circuit traced through its winding from the groundedconductor'305 to the conductor 179 and test contact 17 5 places apotential upon the said test contact 175 and its multiples, which issufiiciently near to ground potential to render the connector H busy tothe toll second selectors. With regard to relay 204, the upper Windingof this relay, which is included in the circuit of line relay 201, is oflow resistance and is not necessarily strong enough to energize therelay by itself, but isstrong enough to hold -'ing system which haveaccess to the the said relay in operated position after it has beencompletely operated by the closure of the circuit through its lowerwinding. In order to reduce the impedance of the upper Winding so as notto interfere with operating impulses transmitted 'to thelinerelay 201,the relay 204i is provided with a copper slug as indicated in the drawinI The connector H is now ready to be operated under the control of thecalling device S, when the dial is actuated in accordance with the nextdigit in the number of the sub scriber at the substation A. A series ofinterruptionsis produced as before, which are repeated by the relay 104of the repeater E to bring about a series of deenergizations of the linerelay 201. At each deenergization the line relay 201 transmits a currentimpulse through the vertical magnet 210 over the following circuit:Ground at G armature 215 and its resting contact, armature 2 16 and itsworking contact, 0E normal springs 222 and 220, winding of the slowacting series relay 203, and winding of the vertical magnet 210 tobattery. This is the circuit over Which the first impulse istransmitted. At the first upward step of the switch shaft, however, theoff normal springs are shifted, and the'circuit extends from the workingcontact of armature 216 by way of off normal springs 222 and 221,armature 217 and-its working contact, (relay 203 being'now energized)winding of the relay 203, and the winding of the vertical magnet 210 tobattery. By the operation of the vertical magnet the switch shaft israised step by step until the wipers 270- 272, inclusive, stand oppositethe level of bank contacts in which the line of substation A isterminated. The slow acting relay 203 which is energized in series withthe vertical magnet, maintains its armature attracted throughout thevertical operation of the switch. lVhen this relay energizes at thebeginning of the'vertical movement it closes the follow ing circuit forthe ring cutoff relay 205: Ground at G armature 218 and its workingcontact, armature 219 and its'working con tact, working contact ofarmature 2'37 and the said armature, and the lower winding of theringcutoff relay 205'to battery. Upon energizing, relayj205 openscontactsincluded in a later established signaling circuit at itsfarmatures 227 and 229, and at its armature 5 1228'establishes a lockingcircuit for itself as follows Grounded conductors 305, working contactof armature 228 and the sald armature I 236 and its workingcontact,and'thelower ,scriber at substation A.

winding of relay 205to battery. At the end of the vertical movement ofthe switch, the slow acting relay 203 deenergizes and prepares theconnector for operation in its ro-i tary movement. 7 e r v The tooloperator now operate the dial of the calling device S in accordance withhe final digit in the number of the sub- The' interruptions produced arerepeated as before through the medium of relay 104-, cause anotherseries of d cenergizations of the line relay20lofthe relay 206 tobattery.

connector H. At each deenergization, the line relay 201 now sends acurrent impulse through the rotary magnet 212 over the following path:Ground at G armature 215 and its resting contact, armature 216 and itsworking contact, normal springs 222 and 221, armature 217 and itsresting contact, resting contact of armature 233 and the said armature,armature 246 and its resting contact, and the Winding of the rotarymagnet 212 to battery. In response to these impulses the rotary magnetoperates to rotate the wipers 270-272, inclusive, into engagement withthe particular set of bank contacts in which the line of substation Aterminates, these bank contacts being the contacts indicatedin thedrawing by the reference characters 273, 274, and 275. gized in parallelwith the rotary magnet and retains its armatures attracted throu houtthe rotary movement of the switch. it its armature 239, relay 208connects the test wiper 271 to the winding of th'e'busy test relay 206,

The slow acting relay 208 is ener-' and at its armature 240, relay 208closes a shunt around armature 233 of relay 206 and its resting contactto guard against the possibility of the saidrelay' being momentarllyenergized while the test wiper 271 is passing 7 over busy test contacts.In order to afford an opportunity to explain the operation of the H busytest circuits it will be assumed that when the line of substation A iscalled at this time it is busy. In such case the testcontact 27 1 willbe grounded and when the test wiper 271 makes connection with thesaidtest contact, the test relay 206 will be energized, thecircuit'being traceable as followszGrounded test contact 27 1, test wiper 2'71,contact springs controlled byarmature 244 of relay 209, armature 239 andits working contact,

arl'nat'ure 243 and its resting contact, and the winding of the testrelay 206 to battery. The 7 test relay is energized over the'abovecircuit and when the slew acting relay. 208 deenergizes at the end ofthe rotary movement of the switch, the test relay becomes locked up by.

means of the following circuit Grounded test contact 274e, test wiper271, working contact of armature 22d and the said armature,

workingcontact of armature 230 and the said armature, contact springscontrolled by armature 239 of relay 208, armature 2 1 3 and its restingcontact, and the winding of the test The various circuit changeseficcted by the operation of the test relay will now lie-briefly pointed(out. Its '7 locking circuit which is closed at armature 230 has ustbeenrexplalned. At armature 231 the circuit of the switching relay 209is opened, at armature .232 a shunt is connected around the armature 236of relay 207 and its working contact in order to prevent accidentaldeenergization of the ring cuto'li' relay 205 (by movenientof ringingkey at the operators cord circuit), at armature 233 the circuit ofthe'rotary magnet 212 is opened in order to prevent the switch wipersfrom being rotated off the contacts of the called line, and at armature235 a lead from the busy signaling machine Q isconnected to the lowerline conductor 181. The conductor 181 extends back through the selectorF to the lower right hand winding of the repeating coil and it followsthat the toll operator will be given an audible busy signal indicatingto her that the called line busy. This busy signaling operation issimilar to methods in common use, and will be understood without furtherexplanation.

The toll operator will now restore her listening key K and may proceedto workon other connections while waiting for the line of substation Ato become idle, first, however, removing the plug from jack Jr in orderto prevent the busy tone from passing out over the toll line. When key Kis restored the supervisory relay 6 is connected in bridge of the trunkconductors 30 and 31 in place of the operators head set and this relay 6would be energized in series with the line relay 104 of the repeater Ewere it not for-the fact that the connector H is waiting on a busy line.In order to make this clear a circuit will be traced which was completedby the busy test relay 206 and which extends as follows: Ground at G,resting contact of armature 241 and the said armature, armature 234 andits working contact, working contact of armature 223 and the saidarmature, conductor 178, bank contact 174, wiper 170, working contact ofarmature 161 and the said armature, conductor 141, armature 123 and itsresting contact, armature 115 and its working contact, upper right handwinding repeating coil R, and the winding of relay 100 to battery.Current flow in the above circuit serves to operate relay 100 whichclosesa circuit for the relay 101. Upon energizing, the latter relaydisconnects the incoming trunk line conductors from the windings of theline relay 104 and at the same time closes a local circuit for the upperwinding of the said line relay. The exchange battery is thus entirelydisconnected from the trunk line and it will be evident, accordingly,that the supervisory relay 6 will not be energized and the lamp L .willnot be lighted.

l/Vhen the line substation A becomes idle, ground potential is removedfrom the test contact 274 and the locking circuit of the test relay 206is broken. The test relay, therefore, deenergizes, disconnects the busysignaling machine Q, opens the circuit of relay 100 at the repeater E,and establishes a circuit for the switching relay 209 which may betraced as follows: Grounded conductor 305, resting contact and armature231, upper winding of the switching relay 209, resting contact ofarmature 239 and the said armature, contact 55 springs controlled byarmature 244, test wiper 271, test contact 274, winding of the switchingrelay 317 of the individual line switch C, and thewinding of thestepping magnet 318 to battery. Upon the closure of the above circuitrelays 209 and 317 are energized in series, and the latter relay isoperated. to disconnect the line conductors 320 and 321 from theirnormal connections in the line switch. Relay 317 is not completelyoperated because of the fact that the line relay of the line switch 1asnot been energized, and does not connect the line conductor with thewipers of the line switch. In the connector H, the relay 209, uponenergizing, opens the circuit of the rotary magnet 212 at armature 246,establishes a locking circuit for itself at armature 245, connectsground G to the test wiper 271 at armature 244, thus closing the circuitof the switching relay 317 of the'line switch over a new path excludingthe upper winding of relay 209 which was formerly included in thecircuit, and at armatures 242 and 247 closes in the preceding paragraph,the circuit of relay at the repeater is broken as previously stated, andthis relay and also relay 101. are deenergi'zed. The incoming trunkconductors are thereby connected again to the windings of the line relay104 and current is supplied to the bridged supervisory relay 6 at theoperators cord circuit. Relay 6 is, therefore energized and lights thesupervisory lamp L to advise the operator that the called line hasbecome idleand that connection thereto has been completed.

The next operation is to ring the subscriber at substation A. For thispurpose the operator throws the key K momentarily to ringing position,thereby projecting ring ing current out over the trunk line with whichthe cord circuit 0 is connected, to operate the alternating currentrelay 121 at repeater E. Upon attracting its armature 128, relay 121breaks the previously described circuit of the relay 207 at theconnector H; Relay'207 accordingly deenergizes and at itsarmature 236breaks the locking circuit of the ring out OK relay 205. Relay 205 thendeenergizes and at its armatures 227 and 229 opens the talkingconductors and establishes the usual signaling circuit which includesthe ringing current generator Gen and its own upper winding. There is nospecial novelty in the signaling circuit itself, although it is believedthat the provision of a pick up relay, which is rendered necessary bythe fact that semi-selective of substation A is a party line, substationA being a so called two bell station while submer locking circuit, t

station A. is a one bell station. The operations following thedeenergizat-ion of the ring cutoff relay 205 may be explained more indetail as follows: When relay 205 fallsv 'mature 28 i finally closes thesignaling circuit,

after which thebell at substation A'will be rung automatically as longas the'receiver remains on the hook. During the ringing operation theoperator is given the well known ringing current induction, provided, ofcourse, that she is listening on the line, to notify her that theringing is proceeding satis factorily. of the inductive path whichextends from armature 2et7 of relay 209 by way of the low capacitycondenser 299 to the resting contact of armature 235 of relay 206.Condenser 299 is of very low capacity, preferably about .005microfaradaand permitsjust enough ringing current to leak'back in: thedirection of the operator togive her an easily distinguished signal. 3

When the subscriber at substation A removes his receiver inresponse tothe ringing of his bell the ring cutoff relay 205 will be operated bycurrentfrom the exchange bat.- tery in series with the ringing currentgenerator Gen, or by current from the exchange battery in series withthe booster battery as sociated with the'generator,and uponattractingits armature 228 will reestablish its torhe operator having restored herringing key by this time to permit the energization of relay 207. Thering out off relay also disconnects its own uper winding and the ringingapparatus at its armatures 227 and 229, respectively, and closes thetalking conductors at these same armatures. The transmitterat substationA is now sup plied with talking battery through the winding of thebattery feed relay 100 at the repeater E. This circuit will not betraced in detail, but it will be observed that the lower line conductorextends uninterruptedly back through the connector H and the selector Fto the lower right hand winding of the repeating coil R, whence itextends through the resistance 113 to ground, while the upper lineconductor 320 extends backthrough the cons nector l and the selector Ftothe-upper right hand winding of the repeating coil R. from which pointit may be traced through the said winding and through the windingot therelay 100 to battery; Relay 100 isenergized by current flow through thetransmitter at substation A, and upon attracting its armature closes thecircuit of'relav 101, which again operates to close a local circuit forline relay 104:, and breaks the circuit of'thesupervisory This isaccomplished by means relay 6 atthe operatorsv cord circuit, thuscausing this relay to deenergize and extindeposited the operator isgiven an audible signal over the telephone circuit in the usual mannerso that she will know that the right amount has been deposited, and alsothe polarized magnet of the paystation is connected to the line in orderthat the operator'may thereafter either collect or refund the coins;

Everything is now in readiness fbrconver- 1 sation to begin, at least sofar as the conne c.- n to the party at substation A is concerned.

wed in the distant exchange, the oper- ,tor' .vill now complete theconnection at her cord circuit the connected parties can conversedesired; It will be observed that suming that the desired party has beenthe connection. includes' a twoconductor trunk line from the toll:switching station to ain or local exchange (the trunk comi rngconductors-'30:and81) ,which is a decided economy over the formerarrangements conductor trunk lines. Another advan tage which may bepointed out is found lnithe arrangement by which the called subscribercontrols the release ot the connection, while his receiver is oft,through the medium of relays and 101, the latter of which controls localcircuit for the line relay 104. This 'angeinent makes it possible forthe toll rater to change cord circuits after a called :ablishedconnection.

rs will hang uptheir receivers; Upon placement of the receiver atsubstation relays 100 and 101 at the repeater E are "core -l th 1' l 104onolicr izec ant. e me .e a is a ain acted across the conductors of theincom- I 6 at the operators cord circuit is enered and the'lamp L islighted to give the operator a disconnectsig'nal. Before releasing theconnection the operator will have to coll e .t whatever coinsweredeposited, and th? operation will now be explained.

The trunk line extending from jack J in the toll switching station tothe connector M in the iocal exchange and comprising conductors 352, and353 is one of a limited r of similar trunks which are used exatrons. Anyone of these trunks may be made se of to collect orrefund at anysubscribers ri hen the connection is finished botlrsub- 0 at least threeand sometimes even party has answered without releasing the es- 7 -unkline. As a result the supervisory station in the local exchan e inuestion which has been connected with via the toll senice trunkingsystem. When the toll ope. or gets ready to collect, then, on theconnection just described, she will insert the plug of special cordcircuit 0 in the jack of an idle collect trunk, and we will assume thatthe trunk line shown in the drawing is the one taken for use. V-Jhen theplug is inserted in jack (i a circuit is completed over the sleeve ofthe jack which includes the calling device S and the relay 350 inseries. Upon energizing, relay 350 lights the busy lamp'L and, itsmultiple lamps at other positions (not shown), and also closes a circuitover trunk :ontluctor 352 Wi'llCll includesthe line relay 360 of theconnector M at the distant local exchange. Upon energizing relay 360closes a c? rcuit tor the slow acting release relay 361 which uponenergizing in turn prepares the circuit of the vertical magnet at itslower armature in the usual manner. Relay 361 also closes a circuitthrough the upper or polarizing winding of the electro-polarized relay364.

The operator will now operate the calling device S in accordance withthe number of the toll service trunk line in use inthe connection forwhich it is desired to collect, it bcing understood that all the tollservice trunks extending to the local exchange in qu tion are numberedconsecutively in acco': .nce with the bank numbering of the connector Mand associated connectors. Assuming that connector H is a one hundredline switch, it may have access to one hundred toll service trunksnumbered from 01 to 99. To proceed, when the. calling device S isoperated in accordance with the first digit of the number the relay 350is deenergized a plurality 0t times, causing a like plurality ctdeenergizations of the line relay 360 o t.

t the connector M. lhe latter relay controls lie connector M insubstantially the same way that the line relay 201 controls thecomh'nation conne tor H and on thataccount the e plnation will not begiven in detail. fly, at each denergization, line relay 360 sends acurrent impulse throughthe vertical magnet 367 which operates to raisethe switch shet't step by step until the wipers 370, 371, and 372 standopposite the level in which is terminated the branch line which is amultiple of the particular toll service trunk to be collected over. Theslow acting'series relay 362 is energized in series with the verticalmagnet, maintains the vertical magnet cirit intact after the oil normalsprings have s t d at the first upward step of the shaft,

" and at the end of the vertical movement deenergizes and shifts theoperating circuit to the rotary magnet 368.

hen the calling device S is operated in accordance with the next andlast digit in the number, the line relay 360 sends a series of currentimpulses to the rotary magnet 368' which in response thereto operates torotate the wipers 370372, inclusive, until they come to rest inengagement with the bank contacts 37 337 5, inclusive. At the firstrotary step the rotary ofi' normal springs 369, which are. included inthe rotary magnet circuit, are separated, but the magnet circuit ismaintained closed by the slow acting series relay 363 until the lastrotary impulse is received after which the said relay deenergizes andthe magnet circuit is opened.

An independent connection has now been established with the toll servicetrunk by way of the collect trunk and the connector M. Vhile the tolloperator is operating the dial of calling device S to establish thebranch connection she has her listening key K in the cord circuit 0 inoperated position and as soon, therefore, as the connector M establishesconnection with the branch comprising con'ductors 30, 300, and 31, and,the slow operation of the connector M, either of which would causeconnection to be established with some other toll service trunk than theone over which it is desired to collect. If the operator does not hearthe tone she willylrnow that something is wrong and will call the numberover again. The manner in which the tone signal is placed on the trunkline will be easily understood, It will be noted that the lower wiper372 of the connector M is connected to the lower terminal of thegrounded secondary winding of the induction coil associated with highfrequency generator Gen, while the upper wiper 370.

is connected to ground through a condenser. With this arrangement whenconnection established with the bank contacts 373-375, inclusive, thesecondary of the induction coil is bridged across the branch conductors30 and 31, resulting in the transmission of an audible signal to theoperator as stated.

Having perceived the O. K. signahthe operator will immediately operatethe collect key winding; but relay 365 is operated and closes thefollowing circuit: From the positive pole of grounded battery B throughthe resistance lamp in series therewith, resting contact of armature 381and the said armature, armature382 and its working contact, inding ofmarginal relay 366, wiper 371, bank contact 37 conductor 300,:1rmatureand its working contact, wiper '72, bank contact, 70, conductor 180,winding of relay 107, and the high resistance 109 to ground. Currentflow in the above circuit operatesrelay 107 the relay 386 remaininginoperative due to the high resistance of relay 107'and resistance 109.

Upon energizing, relay 107 closes a circuit for relay 108 which, uponattracting its armatures 123 and 124;,opens the heavytalklng conductorsat the repeater E and connects con-.

ductors 141 and 14:5 to conductor'130. A relatively lowresistance'branch path to ground is thus established which is inparallel with the relay 107 and resistance 109 and which may be tracedreadily by way of conductors 141, 178, and 320 to the substation A,whence the circuit extends through. the po 7 larized magnet of thepaystation mechanism to ground. Battery B is a high voltage battery andproduces a current flowin the above traced branch circuit which is inthe proper direction to operate the polarized magnet to collect thedeposited coin or coins, the paystation mechanism being reset at thesame time. When the branch circuit through the aolarized ma net isestablished the reSultin 2:; 23

collect circuits are all right and that presum= ably the coins have beencollected. The collect key is now restored and relay 365 is therebydeenergized, whereupon the battery B is disconnected and relays 366,107, and

108 are deenergized. Also, since the paystation mechanism at substationA has beenreset by the polarized .iagnet, when the battery B isdisconnected and the polarized magnet is thereby permitted to restoreits armature the said magnet is disconnected from the line. The tolloperator will now operate her collect key once more, thereby againconnecting battery B to the line of substation A as before described.This time, however, since thepolarized magnet at the paystation has beendisconnected the marginal relay 366 will not be operated and theoperator will not getthe interruptedftone back on the line. By this theoperator knows that the collecting operation has been successful and shewill again restore the collect key.

If the operator desires to refund a deposited coin rather than collectit she may do so by operating the refund key instead of the collect key.Assuming the same circuit conditions to exist as in the previous case,where the operator collected the coins, if the refund key is operatedthe exchange battery is connected 7 her.

in bridge of trunk conductors 3-51 and 353 as before, except that itisreversed, and as a. re-

sult the electro-polarized relay 3% at the con larity, the depositedcoins are refunded in stead of collected. Except as pointed out, therefunding operation is the same as the collecting operation, and theoperator is given supervision bynieans of the interrupted tone in thesame way. a

The special collect trunks are used only for collecting or refunding,which takes but a few seconds, andare at once restored to common use.When the plug is removed from jack J relay 350 is deenergized and breaksthe circuit of the line relay 360 of the conductor M. Relays 3G0 and 361are thereupon deenergized and the s wi'tclris restored to normalby meansof the release magnet 885 in the usual manner.

The release of the main connection over the toll service trunks is alsobrought about by V The busy lamp L r ticed also that relay 21 maintainsa test 120- tential on the sleeve of jack J, which permits the usualaudible busy test circuits to be used in the operators cord circuits ifdesired. Now when the called subscriber hangs up his receiverrelays 100and 101 at the repeater R are deenergized and the line relay 104 isconnected across the incoming trunk conductors as explained heretoforein considering the control of the supervision. The effect of this is toenergize the slow acting relay 22 which was bridged across the trunkconductors 30 and. 31 by the deenergization' of relay 20. Upon enerizing, relay 22 breaks the locking circuit of relay 21, and this latterrelay, upon deenergizing, disconnects relay 22 from in bridge of thetrunk. Relays 22 and 10s are, therefore, deenergized. The latter relaybreaks the circuit of the slow acting release relay 105 and also breaksthe operating cir cuit extending to the connector H. By the latteroperation relays 201. and 202 are deene'r gized and the connector H isrestored by means of release magnet 213 in the usual man- When the relay105 at. therepeater E deenergizes it removesground from the com ductor14 .4, thereby permitting the. switching.

relays 50 and 150 of selectors D and F, respectively, to deenergize.Thereupon these switches are restored by means of their reconnectionwith the present invention, and,

besides, they have already been described in certain of my priorapplications previously referred to; therefore it is believed to beunnecessary to go into such further details now.

What is claimed is:

1. In a telephone system, a party line, a series of automatic switchesincludng a final connector switch for extending a connection to saidline, a common code ringing machine and a plurality of common generatorleads extending therefrom, a source of ringing cur k rent, means in saidringing machine for connecting said source to said leads at intervals inaccordance with different codes, a pick up relay in said connector forconnecting one of said leads to the connected called line to signal adesired station thereon, and a circuit for said relay controlled by saidringing machine and effective to energize said relay only while the saidgenerator leads are discon-' nected from said source of ringing current.

2. In a telephone system, connectors, a called party line, a pluralityof branches of said line accessible from the connectors, code signalingmechanism for applying signaling current to the called line in apredetermined series of alternate live and dead periods, automaticallyapplied means for causing the signaling current to be applied to thecalled line only at the starting of the first live period of the nextseries responsive to the-operation of a connector in eflfectingconnective relation with the called line regardless of the time saidoperation occurs, and automatically applied means for causing a specificsaid code series of signaling current to be'applied to the called linein correspondence with the branch of the called line a connector isoperated into connective relation with so that a difierent code seriesof signaling current will be applied to the called line depending uponwhat branch of the called line is connected with.

3. In an automatic telephone system, automatic connectors, a calledparty line, a plurality of branches of said line accessible from theconnectors, code signaling mechanism for applying signaling current tothe called line in a predetermined series of alternate live and deadperiods, automatically applied means for causing signaling current to beapplied to the called line only at the starting of the first live periodof the next series responsive to the operation of a said connector ineffecting connective relation with the called line regardless of thetime said operation occurs, and automatically applied means for causinga specific said code series of signaling current to be applied to thecalled line in correspondence with the branch of the called line a saidconnector is operated into connective relation with so that aditferentcode series of signaling current will be applied to the calledline depending upon what branch of the called line is connected with.

4C. In a telephone system, a connector switch, a called line, a currentinterrupter having means included in a signaling curconnector to theconnected called line in successive trains of series, automaticallyapplied means made operative solely responsive to efiecting theconnection to the called line for V causing said application ofsignaling current to be initiated, and means controlled by the saidinterrupter whereby the application of any portion of a said train ofseries will be disabled from being initially through the connector afterthe interrupter has started the application of-a train. 7

5. In a telephone system, a plurality of connector switches, calledlines, a current interrupter having means included'in a'multipledsignaling current path, each path including one of said connectors, thesaid interrupter for controlling the application'ot signaling currentfrom a connector to its connected calledline in successive trains ofseries, automatically applied means made operative solely responsive toeffecting the connection to the called line for causing said applicationof signalling current to be initiated, and means controlled by the saidinterrupter whereby the application of any portion of a said train ofseries will be disabled fromvbeing initially applied through a-saidconnector to its connected called line after the interrupter has startedthe application of a train.

6. In a telephone system, a plurality of connector switches, calledlines, a current interrupter having means included in a multipledsignaling current path, each, path including one of said connectors, thesaid interoperative solely responsive to efiecting the Q connection tothe called line for causingsaid application of signaling current tobeinitiated, means controlled by the said interrupter whereby theapplication of any portionof a said train of series will be disabledfrom being initially applied through a said connector to its connectedcalled line after the interrupter has started the application of a trainwithout effecting the application of ourrent/from other of saidconnectors controlled by the interrupter, and means which will enablethe signalling current to be applied over the said disabled connector atthe initiation of the next succeeding train thereafter.

7. In an automatic telephone system, an

automatic connector switch, a called line, a

current interrupter having means included in a signaling current path ofthe connector for controlling the application of signaling current fromthe connector to the connected called line in successive trains ofseries, automatically applied means made operative solely responsive toeffecting the connection to the called line for causing said applicationof signaling. current to be initiated, and means controlled by the saidinterrupter whereby" the application of any portion of a said train ofseriesowill be'disabled from being initially applied through theconnector after the interrupter has started the'application of a train.I

8. In an automatic telephone system, an automatic connector switch, acalled line, a current interrupter having means included in a signalingcurrent path of the connector for controlling the'applicationof'signaling current from the connector to the connected called line insuccessive trains of series, automatically applied means made operativesolely responsive to efiecting the connection tothe called line forcausing said applicaapplied means for causing the signaling current tobe applied to the called line only at the starting of the first liveperiod of the next series responsive to the operation of the connectorin effecting connective relation with the called line regardless of thetime said' operation occurs.

In Witness whereof, Ihereunto-subscribe my name this 8th day ofDecember, A; D.

, JOHN WrcKs;

tion of signaling current to be initiated, and

rent to be applied to the called line only at the starting of the nextlive period responsive to the operation of the connector in effectingconnective relation with the called line regardless of the time'saidoperation occurs.

10. In a telephone system, a connector, a called line accessible fromthe connector, code signaling mechanism for applying signaling currentto the called line in a predetermined i series of alternate live anddead periods,

means for preventing the initial application of signaling current to thecalled line intermediate of a said series, and automatically

